DD208973A5 - PROCESS FOR THE PREPARATION OF DIMETHYL ETHER - Google Patents

Abstract

THE INVENTION METHOD FOR PRODUCING DIMETHYL ETHER FROM CO, H LOW 2 AND, WHERE APPROPRIATE, CO DEEP2 IS SYNTHETIZED BY THAT THE DIMETHYL ETHER IS SYNTHETIZED IN THE PRESENCE OF A CATALYST CONTAINING A TOTAL OF A) CRYSTALLINE SILICONE ACID IN WHICH SOME SILICIUMATOMES IN THE CRYSTAL GRILLE ARE REPLACED ALU. USING THE GENERAL FORMULA 1SI (0.0012-0.0050) ALO LOW Y, WHERE Y HAS A VALUE OF 2.0018 TO 2.0075, B) A MIXTURE OF CU, ZN, CR, OR CU, ZN, AL OXIDES AND / OR SALTS. THE AL CAN ALSO COME TOGETHER WITH CR.

Description

Process for the preparation of dimethyl ether Field of application of the invention

The invention relates to a process for the preparation of dimethyl ether.

Characteristic of the known technical I / am

Dimethyl ether, hereinafter referred to DM ^ is generally prepared with the aid Onea two-stage process, in which firstly from methanol GO and _H2 and optionally synthesized GO ^ and subsequently cleaved from the methanol water to form D & Lri.

Also, there are some methods in which the DME synthesis is carried out in a single operation by combining a methanol synthesis catalyst with a catalyst for the elimination of water, generally alumina.

In the known processes, the methanol synthesis catalyst consists of copper, zinc and grom or of copper, zinc and aluminum, while the catalyst for the elimination of water is generally alumina.

In an embodiment described in DE-OS 2,757,778 (US Pat . No. A177167), a catalyst is used for the DME synthesis, which consists of metal oxides and / or metal salts which have been stabilized by treatment with a silicon compound; the stabilization consists of obtaining the product obtained after the treatment

24 03 8 9 7 - ² - 23.io.i982

AP C 07 0/240 389/7 (60 886/11)

Material resistant to thermal and mechanical forces and to the action of high temperature steam. The metal oxides and / or metal salts used according to this document are generally Al, Gr, La, Mn, Cu or Zn oxides and / or salts or mixtures thereof. The problem which arises in the Catalysts of known type and also in which the above-mentioned DE-OS, is related to the fact that the means used for the removal of water (.Dewatering) only at relatively high temperatures has a significant activity, but where the catalysts for the copper-based methanol synthesis, which are effective at low temperatures and at low pressure, are unstable, so that the catalyst material sinters and an activity loss occurs over time.

The optimum temperature for the removal of water according to the above-mentioned publications is in the range of 280 to 300 ⁰ G, while the catalysts on copper based only have a long service life when used at temperatures in the range of 200 to 260 ⁰ C.

Object of the invention

The aim of the invention is to provide an improved process for the preparation of diethyl ether, with which high "dimethyl ether conversion yields can be achieved even at medium temperatures.

Explanation of the essence of the invention

The invention is based on the object, a catalyst '

O / Π O Q Q 7 -3- 23.10.1932

L * H U O U Zl / AP C 07 G / 24O 389/7

(60 886/11)

Composition which is active in particular at moderate temperatures and allows high ethyl-ethyl ether conversion yields.

It has now surprisingly been found that one can operate at much lower average temperatures and at the same time achieve quite high DMT conversion yields when using a catalyst obtained by intimately mixing powdery crystalline silica and silica gel respectively. containing material substituted with aluminum and powdered oxides or salts of Cu, Zn or Gr (or Al).

The process according to the invention consists in feeding GO and H ₂ and optionally GO ₂ into a reaction zone which is filled with a catalyst of a G-mixture of the following substances:

a) crystalline silica or "SiO ₂ , in which some of the silicon atoms of the silica crystal lattice have been replaced by aluminum and those of the general formula

1Si (O, OO12-O, OO5O) A1 0

where y is a number between 2.0018 and 2.0075,

b) a mixture of Gu, Zn, Gr or Gu, Zn, Al oxides and / or salts, wherein Al auoh may be present together with Gr ₀

240389 7

-4- 23.10.1982

AP G 07 0/240 389/7 (60 886/11)

The crystalline silicic acid used according to the invention and its preparation are described in DL 'OS 2,924,870, which is hereby incorporated by reference.

40 to 70% of all the metal atoms present in the aforementioned catalystase (a + b) are symmetrical. The percentage of copper atoms in the total of the metal atoms (a + b) varies from 15 to 30 $> the content of zinc (atoms) varies from 8 to 15%, the content of ghromes varies from 0 to 10 % (the value of 0 is reached when aluminum is present), and the content of aluminum (atoms) varies from 0.1 to 10 %,

The ME-manufacturing method according to the invention is carried out at a temperature in the range of 150 bia ⁰ 250 G and at a pressure from 4000 to 15000 kPa ·

embodiment

The invention will be explained in more detail with reference to the following examples.

Examples 1 and 2

Ea was prepared a catalyst based on Gu, Zn, Al and silica modified with aluminum according to the following procedure:

676 g (Gu (MO _{3) 2} · 3H ₂ O, 327 g Zn (NOO ₂ '6H ₂ O and 57 g Natriumalumina t was dissolved in 10 liters of water, The solution was heated to 85 ⁰ G and with stirring with a 10 % solution in NaOH in water until the pH vVert reached 7.5.

240389 7

-5- 23.10.1-982

AP C 07 C / 240 389/7 (GO 886/11)

The precipitate was allowed to settle during cooling; the supernatant was drained off and the precipitate was washed repeatedly with water until no more sodium and nitrate ions were present, with repeated pouring and finally i'iltriören,

The precipitate was dried in an oven at 120 ⁰ G in the air. The material was ground to granules no larger than 0.84 mm (20 mesh ASTM) and mixed with 325 g of silica modified with aluminum and prepared according to Example 5 of DE-OS 2,924,870.

The powder was pressed into pellets with a diameter of 4 mm, and a length of 6 mm. "

Gu, Zn, Al and Si were present in the catalyst in an atomic ratio of 28: 11: 7: 54.

100 ml of catalyst was added to a 2.54 μm diameter tubular reactor.

A sleeve with an outer diameter of 8 mm for a thermocouple was placed axially in the center of the reactor. The temperature was gradually increased by feeding a mixture of H ₂ and N ₂ into the reactor to reduce the catalyst under controlled conditions.

Once the temperature reached 220 ⁰ G and the catalyst reduction was complete, the pressure on 7000 kPa was recycled and the mixture of H ₂ 'and N ₂ gradually replaced by a 1: 1 mixture of GO and H ₀ with a "0urch -

i Set speed of 2 100 h ~ (völumen / Volumen.h).

7 " ⁶ ~ 23.10.1982

I ^ Q ₀₇ g / 240 389/7

(60 886/11)

The catalyst temperature was stabilized in Example 1 at 200 C and in Example 2 at 230 ⁰ C.

Daa formed in the course of the reaction water. Methanol and part of Diinethgrlethers were condensed in a reactor nachgeechelten cooler. Daa condensed water, the methanol and dimethyl ether were removed under pressure and analyzed by gas chromatography.

The gas exiting the reactor was fed to an inlet valve of a gas chromatograph and analyzed and then into an integrating flowmeter to measure the amount of gas.

In Table 1, the results obtained under the above conditions are summarized, by-products which were present in an amount of less than 1 % were not considered.

Table 1

Throughput T P Re selectivity of the CO

wall conversion into

h 'H ₂ ZOO ⁰ G kPa Mol # # DME GH ₃ OH GO ₂

example

1 2100 1 200 7000 22 61.8 4.1 34.1

example

2 2100 1 230 7000 69 63.4 3.0 33.6

24 0 3 8 9 7 -7- 23.10.1982

AP 0 07 C / 240 389/7 (60 886/11.)

Examples 3 and 4

A catalyst was prepared on the base of Gu, Zn, Gr, Si and Al, in which the components were present in an atomic ratio of 20: 12: 8: 60: 0.2:

1,600 g of Gu (MO ₃ ) ₂ .3H ₂ O, 1,182 g of Zn (HO ₃ ) ₂ .6H ₃ O and 1,060 g of Cr (NO ₃ ) ₃ .9H ₂ O were dissolved in 20 liters of distilled water. The solution was heated to 95 ⁰ G and 20 liters of an aqueous solution of 1 300 g of NaOH added with stirring. The precipitate was cooled, washed with water to drip, filtered and washed repeatedly with water. The Miederschlag was dried in an oven at 120 ⁰ G. The material was ground to granules <L 0.84 mm and then mixed with 1 192 g of silica modified with aluminum (Example 5 of Dü ^ -OS 2,924,870).

Pellets were made with a diameter of 4 mm and a length of 6 mm. 100 ml of catalyst was tested under the same conditions as in Examples 1 and 2; the results are shown in Table 2.

Table 2

Throughput T P Um- "Selectivity of

wall GO conversion into

-1 η ^lun S

h 'H ₂ / GO ⁰ G kPa Idol-56 DLM CH ₃ OH

Example 3 2100 1 200 7000 12 62.6 3 »8 33.6

Example 4 2100 1 230 7000 45 64.7 1.8 33.5

2403 8 9 7 _ ₈ _

23/10/1982

AP G 07 C / 240 389/7

(60 886/11)

Examples 5 and 6 (for comparison)

The catalyst according to Example 1 of US Pat. No. 4,177,167, in which the atomic ratio C, Ou: Zn: Gr: Al 20: 12: 8: was under the same conditions as in Examples 1 and 2 tested * The results are listed in Table 3.

^: j '-: u; XA T a be 1 1 e 3 λ.-. , , "·

Throughput T P Re selectivity of

wall GO conversion in lung,

_Mol _ ^ dme GH ₃ OH GO ₂

game 5 2100 1 200 7000 11 11.9 54.0 34.1

Example 6 2100 1 23O 7000 42 18.5 47.0 35.0

This Vergleichabeiapiele show that at low operating temperatures of the catalyst on the B _a ais of stabilisertem .Aluminum not enough activity for the cleavage of water unfolded so that DME is present only in small amounts or = arises. y

Claims (3)

23.10.1982 AP G 07 G / 240 389/7 (60 886/11) & rfindunffsanapruch 1Si (0.0012-0.005O) Al O corresponds to where y has a value of 2.0018 to 2.0075, b) a mixture of Cu, Zn, Gr or Gu, Zn, Al oxides and / or salts, in which Al may also be present together with Cr. 1. A process for preparing dimethyl ether from CO, H ₀ and optionally GOp, characterized in that the ^ ime thy let forth is synthesized in the presence of a catalyst consisting of a) crystalline silicic acid in which some silicon lattice of the crystal lattice is replaced by aluminum and that of the general formula 2. The method according to item 1, characterized in that the catalyst is a total of 40 to 70 atom% Si, 15 to 30 atom% Cu, 8 to 15 atom-jS Zn, 0 to 10 atom% Cr and 0.1 to 10 atomic% Al, based on the total amount of metal atoms, 3. Catalyst for carrying out the method according to item or 2, characterized in that it consists of a) crystalline silica, in which some of the crystal lattice are replaced by aluminum and 03 8 9 7_ _1O _ ₂₃ . ₁₀ .i ₉ 82 AP G 07 0/240 389/7 (60 886/11) that of the general Forinel 1Si (0.0012-0.005O) Al where y has a value of 2.0018 to 2.0075, and b) a mixture of Gu, Zn, Gr or Gu, Zn, Al oxides and / or salts, in which Al may also be present together with Gr.